A new automatic turntable flame welding system based on PLC is put forward to solve the problems of low degree of automation, low production efficiency and poor flame stability in parallel flow condenser welding. Every station can run synchronously and link up tightly by a four-station turntable. Human-computer interaction is easy to operate by using the configuration software to complete the system interface design. Control algorithm uses fuzzy control. System uses PLC, flow sensor and regulator to form a feedback unit and rely on real-time flow information to adjust the parameters of the fuzzy logic system. Besides, system adjusts air and gas flow through optimal control parameters calculating online. The experimental results show that comparing with conventional control, fuzzy control has smaller steady state error, shorter stable cycle. Through the analysis of the machine capability index Cmk, the flow control precision meets industry requirement. The system is stable and reliable in actual production and the welding qualification rate reaches 99.5%.